In network virtualization technologies of a data center, multiple heterogeneous hypervisors may be utilized to coordinate in accessing different physical devices and virtual machines (VMs). Virtual switches (vSwitches) configured in hypervisors may provide communication capability among VMs and between VMs and external networks. These hypervisors and vSwitches may be managed by different hypervisor managers. Since vSwitches managed by different hypervisor managers may go online in in different ways, different hypervisor managers may be controlled by different Soft Defined Network (SDN) controllers or an SDN controller cluster. However, different SDN controllers cannot sense each other's overlay networks. Therefore, direct communication may likely be unavailable for VMs running on the heterogeneous hypervisors via overlay networks.